Scroll a movieclip, help plz

Did this ever have any chance of working?

//create scrollable clip
this.spons.scrollRect = new flash.geom.Rectangle(0, 30, 460, 160);
this.spons.cacheAsBitmap = true;
//------------------------------ code for scrollers -----------------------\\
btn_upscroll.onPress = function() {
 target = this.spons;
 var scrollUp = target.scrollRect;
 var scrollmax = target._y;
 if (scrollUp.y>scrollmax) {
  scrollUp.y -= 10;
  target.scrollRect = scrollUp;
btn_downscroll.onPress = function() {
 target = this.spons;
 var scrollDown = target.scrollRect;
 var scrollmax = scrollDown.height;
 if (scrollDown.y<scrollmax) {
  scrollDown.y += 10;
  target.scrollRect = scrollDown;
//------------------------------ end scroller code -----------------------\\

‘spons’ is the instance name of the MC I’m trying to scroll and btn_downscroll/upscroll are the instance names of buttons that I’m hoping would scroll the MC. Is it possible and if so why isn’t it working.
Also, I noticed that while the scrollRect is creating the mask just fine, the MC behind it is ‘centered’ so that you see the middle but not the top or the bottom. Very odd. Any way to fix that or am I going about this totally the wrong way? appriciate any assistance.